Is lagundi (Vitex negundo) an antitussive for mild dry cough in healthy adults, and what dosage and safety issues should be considered?

Is Lagundi an Antitussive?

Yes, lagundi (Vitex negundo) has demonstrated antitussive properties in animal studies, but it lacks high-quality human clinical trial data and is not recommended in evidence-based guidelines for cough management, which instead prioritize dextromethorphan, honey-lemon mixtures, or menthol as first-line treatments. 1, 2

Evidence for Lagundi's Antitussive Effect

Animal Study Data

• Lagundi butanolic extract demonstrated dose-dependent cough suppression in mice exposed to sulfur dioxide-induced cough, with maximum effect at 1000 mg/kg showing 67.4% cough inhibition at 60 minutes 3
• This compares to codeine (10 mg/kg) at 75.7% and dextromethorphan (10 mg/kg) at 74.7% inhibition in the same animal model 3
• The LD50 was greater than 5000 mg/kg with no signs of neural impairment or acute behavioral toxicity at antitussive doses 3

Critical Limitations

• All antitussive evidence for lagundi comes from a single animal study in mice—no human clinical trials exist demonstrating efficacy for cough suppression 3
• The British Thoracic Society explicitly notes that animal models of cough are often not predictive of effects in humans, as evidenced by high compound attrition rates from preclinical to clinical studies 1
• No guideline from major respiratory societies (British Thoracic Society, American College of Chest Physicians, CHEST) mentions lagundi as a recommended antitussive agent 1, 2

Recommended Evidence-Based Alternatives

First-Line Treatments for Dry Cough

• Honey and lemon mixture is the simplest, cheapest first-line treatment with evidence of patient-reported benefit 2, 4
• Dextromethorphan is the preferred pharmacological agent with maximum efficacy at 60 mg doses, offering superior safety compared to codeine-based alternatives 2, 4
• Standard over-the-counter dextromethorphan dosing (10-15 mg) is often subtherapeutic; maximum cough suppression occurs at 60 mg 2, 5

Alternative Options

• Menthol by inhalation provides acute but short-lived cough suppression 2, 4
• First-generation sedating antihistamines may be used for nocturnal cough due to their sedative properties 2, 4

Safety and Dosing Considerations for Lagundi

Lack of Standardized Human Dosing

• The animal study used 250-1000 mg/kg doses, which cannot be directly extrapolated to human dosing 3
• No established therapeutic dose range exists for humans
• Product authentication is a significant concern—only 1 out of 5 lagundi herbal products tested in the Philippines contained authentic Vitex negundo 6

Quality Control Issues

• Adulteration, substitution, and contamination are documented problems with lagundi products in the Philippine market 6
• Without standardized quality control, the actual content and potency of commercial lagundi products is uncertain 6

Clinical Algorithm for Cough Management

For Mild Dry Cough in Healthy Adults

1. Start with honey and lemon mixture as a non-pharmacological approach 2, 4
2. If additional relief needed, use dextromethorphan 30-60 mg (not standard 10-15 mg doses) 2, 5
3. For nighttime cough disrupting sleep, consider first-generation antihistamines 2, 4
4. For quick but temporary relief, menthol inhalation 2, 4

Red Flags Requiring Medical Evaluation

• Cough with hemoptysis (coughing up blood) 1, 2
• Breathlessness or tachypnea 1, 2
• Prolonged fever and feeling unwell 1, 4
• Symptoms persisting beyond 3 weeks 1, 2

Critical Pitfalls to Avoid

• Do not rely on lagundi as a proven antitussive in humans—the evidence base consists only of animal studies 3
• Avoid using subtherapeutic doses of dextromethorphan (less than 30-60 mg) if choosing pharmacological treatment 2, 5
• Do not use codeine-containing products, which have no efficacy advantage over dextromethorphan but significantly more adverse effects 2, 4
• Be aware that lagundi products may be adulterated or misidentified, compromising both safety and efficacy 6